A necessary step in altering a patient's tooth color is to determine the “shade” of the existing tooth. For example, those persons seeking a whiter, brighter smile are still assessed to establish their existing tooth color so that an appropriate before and after comparison can be made. Shade determination is even more important for those persons seeking reconstructive work, since one goal of the reconstructive process is to achieve a natural appearance. Therefore, it is important to know the existing tooth shade so that it can be accurately matched with the new restoration.
The dental profession has typically utilized standardized shade guides created by those companies which manufacture the reconstructive materials. One well-known shade guide is the Vita™ shade guide, which includes sixteen different shades. Other, less popular shade guides include those guides provided by Bioform™ and SR-Vivaden™.
These shade guides are utilized in a rudimentary fashion. The guide itself is a plastic plate with a plurality of removable color tabs that are shaped like a tooth, e.g., the front tooth. Typically, to assess a patient's tooth shade, a dentist removes one of the colored tabs and holds it up to the patient's tooth so that she can “eyeball” the closest match possible. Understandably, there are many variables to this method, some of which stem from the subjectivity of the dentist making the eyeball assessment.
To further complicate matters, the standard Vita™ Classic shade guide contains only sixteen shades ranging from A1 to D4. Needless to say, many patients' teeth do not match any of the sixteen shades. In that case, if the eyeball assessment is used, the dentist may attempt to combine two or more shades. Alternatively, if a computer or electronic shade analyzing system is being used, the analysis may result in a determination that the shade is almost exactly in between two shades. For example, a tooth may be 49% A4 and 51% B1 according to the analysis. In that case, the system will typically report the shade as B1, since that is the closest match.
Once the tooth shade is determined, the information is used relative to the particular procedure needed. In bonding or filling a tooth, for example, the composite materials required for the restoration are specified within the range of the shade guide, e.g., one of sixteen shades for the Vita™ range. More particularly, if a crown, bridge, or denture is needed, the patient's shade must be determined and communicated correctly to the lab that make the crown, bridge, or denture.
The process for selecting the porcelain for a particular tooth shade illustrates the difficulty in assessing and manufacturing the correct color match. If, for example, a crown of Vita™ shade A3 is desired, porcelain is built by hand with a paint brush onto a model of the tooth to be restored. The porcelain is built in layers on the model to achieve translucency and natural appearance. Each layer has a particular color and intensity associated with it. To generate shade A3, the technician follows a “recipe” that is given by the manufacturer Vident™, requiring a different shade for each layer of porcelain applied. If a doctor asks for a shade that is not a Vita™ standard shade, the technician typically seeks to achieve that shade by combining different porcelain shade combinations together, to increase or decrease the chroma, hue, and value of the shade.
Patients may also desire to change the shade of their teeth, generally by whitening or otherwise brightening them. A necessary first step in this regard is to determine the shade of the existing teeth. The goal may be to whiten all of the teeth to a certain predetermined shade, or it may be to match the shades of some of the teeth to the others. Currently, the dental professional will utilize a standardized shade guide, such as VITA™, BIOFORM™, and CHROMASCOP™. There is a great deal of subjectivity involved in such a measurement and the dental professional may not be sufficiently skilled or qualified for the task. The lighting and ambient light in the room can also affect selection of the tooth shade.
Thus, there is a need for a shade guide system for obtaining accurate color information from a patient wherein reliable, reproducible information is obtained regarding the shade of the patient's tooth. The shade guides known in the art are too limited to provide enough options to accurately match a patient's tooth color. The present invention provides these and other features in a manner which is not heretofore known in the art.